1. Field of the Invention
The present invention relates to a projector employing multiple organic electroluminescence (OEL) image panels, in which each image pixel is represented by a light-emitting OEL component. The new structure for the projector provides the features of downsized dimensions, luminous efficiency and image focusing capability.
2. Description of Related Art
The structure of a conventional light projection device includes a light source for white light, a light splitter, three separate image panels of red (R), green (G) and blue (B) prime colors and a light-mixing apparatus. The basic operating technique of the device includes the following steps.
(1) White light as a light ray is output by the light source.
(2) the light ray is then processed by a light splitter (i.e. Dichroic mirror) and filtered to derive red (R), green (G) and blue (B) colors separately.
(3) The light rays of prime color are then reflected evenly onto three corresponding image panels.
(4) Then the intensity of the prime color ray passing through or being reflected on each point of the image panel is controlled by brightness for the corresponding image element.
(5) Prime color images in gray scale are output from the individual image panels.
(6) These three images of prime color in gray scale are refocused on a light mixing apparatus by image superposition to produce a full color image.
However, the structure of the conventional projector described still has the following drawbacks.
(1) For continuous light modulation by a transmission type and reflection type of image panel, the light ray output from the light source needs to pass through the light splitter to sort out the prime colors before reaching the image panel. Since the light source and light modulation apparatus are independent units, light rays of prime color have to be fed uninterruptedly and uniformly to the corresponding image panels. If the image to be displayed contains large segments of black or dark colors, the light source still has to output white light and then let the three image panels block off most of the light to form black or dark images. Such method suggests considerable waste of luminous resources.
(2) To attain even luminescence on the output image, white light passing through the light splitter to produce the three prime colors has to be sufficiently strong and exceptionally uniform, and other optical apparatus is also needed for the light modulation. No matter what kind of optical apparatus is used, it is difficult to attain perfect uniformity in light modulation, not to mention other problems such as additional light modulation, losing more light energy and lower luminous efficiency.
(3) With an increased number of components in a projector, light passing through the system is likely to attenuate. When the luminous efficiency goes down, the unused light energy will be converted to thermal energy. If the projector generates large amounts of heat, it will considerably reduce the operating life of the internal components, thereby causing heat dissipation problems. It will also have negative impact on the efforts to further reduce the size of the projector design.
The main objective of the present invention is to provide a projector using an OEL image panel. The OEL image panel with light-emitting capability can replace the light source and light splitter in conventional projectors, such that the size and complexity of the projector can be reduced.
Another objective of the present invention is to provide a projector using an OEL image panel, wherein the intensity of light emission can be controlled through the voltage driving the OEL component. Under such condition, luminescence of the image can be appropriately adjusted to prevent any waste of resource resulting from unwanted light.
The image panel having OEL components forms the main part of the projector proposed in the present invention, and the projector comprises one or more image panels, a light correction means and an imaging apparatus. Each image panel is formed with multiple OEL components. The light correction means corrects the projection angle of image signals from individual image panels while reducing light attenuation. The imaging apparatus composes prime color image signal in gray scale output from individual image panels to produce a full color image.
The features of and methods used in the present invention will be more clearly understood after a careful reading of the detailed description with appropriate reference to the accompanying drawings.